The present invention relates to stick lever units, which are capable of creating control signals for maneuvering of models, control of industrial machines, manipulation of game consoles, and the like.
Generally, stick lever units for creating control signals are attached to radio controlled transmitters for maneuvering models, respectively. The basic structure of a conventional stick lever unit will be explained below by referring to the schematic diagram of FIG. 12. A first variable resistor 101 is attached to the outer side of a frame fixing member 100, which is attached on the housing of a radio-controlled transmitter. A first rotational member 104 having a frame shape is rotatably journalled inside of the fixing member 100 by means of the shaft 102 of the first variable resistor 101 and by means of one rotational shaft 103 coaxial to the shaft 102. A second variable resistor 105 is attached outside the first rotational member 104. A second rotational member 107 with a stick 106 is rotationally journalled inside the first rotational member 104 through the shaft 108 of the second variable resistor 105. Wiring conductors 109 of the first variable resistor 101 are connected to the control substrate (not shown). Wiring conductors 110 of the second variable resistor 105 are externally derived beyond the frame wall of the fixing member 100 and are connected to the control substrate.
The rotational shaft 103 of the first rotational member 104 (or the shaft 102 of the first variable resistor 101) is perpendicular to the rotational shaft of the second rotational member 107 (or the shaft 108 of the second variable resistor 105). Accordingly, when an operator manipulates the stick lever 106 attached to the second rotational member 107 in given directions with his fingers, the two variable resistors 101 and 105 are controlled suitably and rotatably, so that control signals of two kinds are created.
A radio-controlled transmitter for a model airplane, for example, respectively manipulates the rudder and the elevator, each which controls the attitude of the model airplane, by means of two servomotors mounted on the fuselage. With one stick lever unit mounted on the radio-controlled transmitter, allocated for control of the rudder and the elevator, control signals for two servomotors respectively driving the rudder and the elevator are obtained by controlling one stick to control the attitude of the airplane. Japanese Utility Model Laid-open Publication No. 57-169393 and Japanese Utility Model Laid-open Publication No. 62-87697 disclose a further specific structure of the above stick lever unit.
In the conventional stick lever unit, the first rotational member 104 is attached to the second variable resistor 105 by rotating the stick 106. As a result, the whole of the wiring conductors 110 derived out from the second variable resistor 105 through the fixing member 100 moves largely. This works as a resistance when the stick 106 is operated which causes an uncomfortable feeling to the operator.
Since the wiring conductors 110 from the second variable resistor 105 always moves together with the first rotational member 104, the wiring conductors 110 undergo repeatedly deformation such as expansion, contraction, twisting, and the like. This repeated deformation over a long period of time may cause the wiring conductors 110 to break.